I know not everyone is a geek. Not everybody wants to calculate costs per kilowatt hour (KWh) for light bulbs or figure out which ones are most efficient and cause the least greenhouse gas emissions. That's why you have me. And that's why I have the light bulb comparison spreadsheet from productdose. Because I don't feel like doing it either but I want the information.
The jist is that if you want to save both energy and money, you should buy compact fluorescent (CFL) bulbs. If you want to save even more energy and are less concerned about the money, you should buy Light Emitting Diode bulbs (LEDs). Since the up-front costs of the LEDs are so high, it's probably still a better idea to buy CFLs for most purposes. The more your electricity costs, the more you save by using LED bulbs. If you can get LED bulbs cheaper than the $54.95 per bulb quoted here, then this calculation favors LEDs even more.
Here is a summary of information about your three favorite types of light bulbs with the light equivalent of an incandescent 60 watt bulb, using a cost per KWh of ten cents:
- Incandescent bulbs (the regular old light bulb) last an average of 1,500 hours and cost $1.34 each. In an average house with 30 light bulbs they will use about 3,285 KWh per year, emit carbon dioxide equivalents (CO2e) of about 4,500 lbs (using estimates for Maryland), and cost $328.50 in electricity per year and 53.80 in light bulbs, a total of $382.30.
- Compact Fluorescents (CFLs) last an average of 10,000 hours and cost $2.98 each. In an average house with 30 light bulbs they will use about 767 KWh per year, emit carbon dioxide equivalents (CO2e) of about 1,051 lbs (using estimates for Maryland), and cost $76.65 in electricity per year and $17.88 in light bulbs, a total of $94.53, a savings of $287.77 over incandescent bulbs.
- Light Emitting Diode bulbs (LEDs) last an average of 60,000 hours and cost $54.95 each. In an average house with 30 light bulbs they will use about 329 KWh per year, emit carbon dioxide equivalents (CO2e) of about 451 lbs (using estimates for Maryland), and cost $32.85 in electricity per year and $54.95 in light bulbs, a total of $87.80, a savings of $294.50 over incandescent bulbs. Buying 30 of these bulbs costs $1,648.85 so it's more cost effective to buy CFLs at this point for most uses unless your electricity costs are high or if you can find cheaper LED bulbs.
Note that all CO2e emissions are zero if you use renewable energy or purchase green tags to support the production of renewable energy.
5 comments:
On 5/7/07, William Moore wrote:
>
> Hi,
>
> How can a led bulb coasting $54.95 ea save me money even though a fluo costs
> $2.98 ea and uses twice as many kw. I see that the led lasts 6 times as
> long. I could buy about 20 fluo for the price of i led. dut
>
> dad
Because the LED uses less electricity. The LED bulb itself costs more over time than the CFL (it's on par with the incandescent) but it uses a lot less energy so your main savings are in reduced energy consumption. You will pay about $17.88 in a year for CFLs and $54.95 for LEDs because you are spreading the cost out over the life of the bulbs. You will pay up-front $89.40 to buy 30 CFLs (unless you get them on sale and I know you will) and $1648.50 for 30 LEDs.
Each one of those bulbs will be used for about 1,825 hours a year if you assume you will have them on five hours a day. A CFL will last 10,000 hours which means that each light bulb will last 10,000/1,825 = 5.48 years. An LED will last 60,000 hours so that each bulb will last 60,000/1,825 = 32.87 years.
The CFL will consume 0.06 KWh electricity per hour. That amounts to 0.014*1,825 = 25.55 KWh per year. Since there are 30 of them, that is 766.5 KWh. My electricity costs $0.10/KWh which is 766.5*0.10 = $76.65 per year. The LED will consume 0.006 KWh per hour, which will cost 10.95 per year. Times thirty bulbs, that's $328.5 KWh or $32.85 per year.
If you add the costs of the bulbs and electricity together, CFLs cost $17.88 per year for 30 bulbs plus $76.65 for their electricity consumption. That is $94.53. For LEDs, it's $54.95 in bulbs plus $32.85 in electricity, amounting to $87.80 per year.
A good question to ask is "how long will it take me to see the cost savings from purchasing $1648.50 in LED bulbs instead of purchasing $89.40 in CFLs?" The answer, if you are not applying an investment rate, is how long will it take me to save $1,559.10? And the answer is about 231 years. However since LEDs use less than half the electricity that CFLs use and a tenth of what incandescents use, they have an advantage in that they cause less greenhouse gases to be emitted.
CFLs use .014 KWh/h. Not .06.
I havn’t turned a light on for more than a minute at a time for a while now. I use lamps….talk about a savings. The best way to save money, and energy is to just not use it. My electric bill is consistently around a 150 kW-hr per month in a 2200 sq-ft house, with electric stove and dryer. The question is…what is it worth to you?
My house runs between 42 degrees and 50 degrees (F) right now and I hang dry my clothes. My total utilities (including internet) per month are under $125 (electric, water, propane, and internet). And so you know I do weld at least a couple things a month on a 200 Amp GMAW welder plugged into 220V 50 Amp circuit.
So, with that said, I am not really in this to save energy, but money. So what’s it worth to you?
Green house tree hugger got nothing on this redneck hot rod builder. Yes I ride motorcycles and like trucks and Jeeps and all that other enjoyable stuff but I have the balls to do what it takes to get what I want...and the fact is I don't know any environmentalist willing to do what I do. So bring it on hippy, use less energy than me. By the way I don't use much fuel either.
"Green house tree hugger got nothing on this redneck hot rod builder...so bring it on hippie"
I don't know why but I love this comment, even though it's trying to pick on me. I think the whole point is that hippies aren't the only people who can benefit from energy conservation, so thanks!
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